The present invention relates to vascular grafts. More particularly, this invention relates to a graft suitable for replacement of the entire aortic arch.
Replacement of the entire aortic arch presents a significant challenge to the cardiac surgeon. Exposure of the descending aorta is much more difficult than exposure of the ascending aorta, which is itself difficult to expose. Accordingly, the vast majority of aortic surgical techniques call for inserting a folded graft inside the descending aorta by suturing the edge of the folded graft first to the rim (cut edge) of the descending aorta, then inverting the graft to straighten it and let it fall within the descending aorta, followed by expanding and fixing the graft against the descending aortic inner wall.
The folded graft procedure summarized above requires a fairly long period of complete deep hypothermic systemic cardiac arrest, in which the patient's body is cooled to a deep level and blood circulation to the entire body is stopped. Surgeons attempt to minimize the duration of deep hypothermic systemic cardiac arrest for obvious reasons.
However, bleeding from the suture line where the graft has been attached to the descending aorta is a common problem. The need to control bleeding often requires maintaining the patient on deep hypothermic arrest for a longer period of time, which increases the risk of neurologic and other organ injury.
U.S. Pat. No. 6,770,090 discloses an anatomically curved aortic arch graft. The graft's curvature is said to better conform the graft to the natural curvature of the aortic arch without kinking.
U.S. Pat. No. 6,187,033 discloses an aortic arch graft in which three tubes adapted for attachment to the brachiocephalic artery, left common carotid artery and left subclavian artery are each joined to the elongate tubular main wall of the graft by means of a common tubular branch wall extending laterally from the tubular main wall.
“E-vita Open The Endoluninal Stentgraft System for Open Heart Surgery” (JOTEC GmbH 2005) discloses a graft having two segments: a short segment (“cuff”) of a conventional vascular graft which is joined to a stent-graft. The cuff is designed to be attached to another, separate graft which replaces the aortic arch and the ascending aorta. The joint between the first segment and the stent-graft is reinforced with a metal ring and sutures to maintain a stable, impermeable connection between the first segment and the stent-graft. This graft relies upon its stent section to fix itself against the descending aortic wall, and can suffer from the problem of bleeding from the suture line where the graft is attached to the descending aorta.
“Gelweave™ Thoracic and Thoracoabdominal Graft Geometries” (Vascutek Undated) discloses a 4 branched graft having a collar designed to compensate for differences in diameter between the distal aorta and the graft. The collar functions as a sewing ring, and must be trimmed to fit the patient's aorta, which undesirably increases the duration of deep hypothermic arrest. Secure placement of the junction between the two graft segments at the open end of the descending aorta is difficult due to the discrepancy between the trimmed collar's diameter and that of the graft. Moreover, conventional sutures must be used to attach this graft, which increases the probability the suture line will bleed.
U.S. Pat. No. 5,163,954 discloses a suture ring for heart valve prostheses having an internal surface or coating which is substantially water repellant, and an outer surface or coating which is substantially hydrophilic and porous.